Optogenetic System and Method

Abstract

An optogenetic system and method for preventing or halting seizures. The system and method use a sensor for monitoring the activity of a neural network containing a group of target neurons, and generating an input signal indicative of said activity, the target neurons being excitatory neurons. Excitatory stimulation is delivered in the form of an optical signal by an optical stimulator to the target neurons, the optical signal being determined based on the input signal, to reduce the overall activity of the target neurons.

Description

FIELD OF THE INVENTION[0001]The present invention relates to an optogenetic system for the halting or prevention of seizures, a control device for use in such a system, and a method of halting or preventing seizures.BACKGROUND OF THE INVENTION[0002]The brain is made up of around 100 billion neurons, which are responsible for transmitting signals throughout the body, in the form of propagating electrical pulses. These pulses propagate in the form of an action potential. Action potentials arise when a threshold potential difference is applied across the neuron membrane (also referred to as a membrane potential), and are seen as a spike in the potential difference across the membrane, i.e. a rapid depolarization. Prolonged stimuli, rather than affecting the amplitude or duration of an action potential, instead result in a series of identical action potentials, the frequency of which depends on the intensity of the stimulus. When an action potential is generated in a neuron, this may be...

AI Technical Summary

Benefits of technology

[0016]an optical stimulator for delivering an excitatory stimulus in the form of an optical signal to the target neurons, the optical signal determined based on the input signal, to reduce the overall activity of the target neurons.

[0017]Herein, “prevention” or “preventing” of seizures refers to cases in which the seizure does not begin at all, i.e. the patient does not have a seizure. “Halting” refers to cases in which the seizure does begin, but is swiftly stopped due to the operation of the optogenetic system as claimed. The advantages of this invention, and the mechanism by which it is able to achieve these advantages, are best understood from a consideration of the “state space” representation of the brain. This is explained in detail with reference to FIGS. 3A and 3B in the “Detailed Description” section of this application.

[0018]In the present application, the term “excitatory neuron” refers to a neuron which releases primarily excitatory neurotransmitters, i.e. those which act to stimulate an action potential in other (post-synaptic) neurons. Examples of excitatory neurons which may form the target neurons of the present invention are glutamatergic neurons. Here, and throughout the application, reducing the “overall activity of the target neurons” (or similar) generally refers to a decrease in the level of activity which is monitored by the sensor. For example, this decrease in activity may refer to a decrease in the number of action potentials discharged by the target neurons. The activity may be associated with seizures or seizure-like events (SLEs), and thus a reduction in the overall activity may advantageously lead to the prevention or halting of seizures or SLEs.

[0019]The target neurons are preferably genetically modified to respond to optical stimuli. The target neurons are excitatory neurons, and they are preferably genetically modified to execute excitatory behaviour in response to an optical stimulus. The target neurons may be modified by using a virus to infect the cells with the opsin DNA. The virus may be injected into the brain and infects neurons in the vicinity. Expression is preferably restricted to only the excitatory cells. Though in other embodiments both excitatory and inhibitory neurons may express the (excitatory) opsin. “Excitatory behaviour” refers to behaviour which stimulates an action potential in the neurons expressing the opsin, such as the opening of ion chan

Problems solved by technology

In “electronic only” systems, the application of electronic stimuli cannot be performed

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